Feature: 1. Super thin Type Electricity Display: 5 Pieces indicator lamps. 2. Wide Application Fields:lithium battery pack. 3. Using Method: connect display board positive and negative terminals with tested battery positive and negative port. 4. Slightly hold down the red button with your finger, then lights will be on and show real-time battery electricity quantity.(Note: The first light is for power Indicator light) 5. Release the finger, the lights will be off after 3-5 seconds delay, it completely does not consume electricity when in the static state. 6. With anti-transposition function, even if the positive and negative ports are connected with wrong direction and it will not burn, simply correct it. Lithium Battery Pack Display Electricity Quantity Parameter: (note: N represents battery quantity) 1. When battery voltage is over N*3.2V, it will illuminate 1 block electricity quantity. 2. When battery voltage is over N*3.4V, it will illuminate 2 blocks electricity quantity. 3. When battery voltage is over N*3.6V, it will illuminate 3 blocks electricity quantity. 4. When battery voltage is over N*3.9V, it will illuminate 4 blocks electricity quantity. 5. When battery voltage is le than N*3.2V, 4 blocks display will be off; it represents battery is le than 3.2V, and you can charge the battery. Specification: Material: Plastic and Metal Size: 40152.5mm/1.570.590.10in (Approx.) 2S lithium battery, full charge 8.4V3S lithium 12V battery, full charge 12.6V4S lithium battery, full charge 16.8V5S lithium battery, full charge 21V6S lithium battery, 24V, full charge 25.2V